The replication initiator protein of plasmid pSC101 is a transcriptional repressor of its own cistron.
The replication initiator protein of plasmid pSC101 is a transcriptional repressor of its own cistron.
复制标题
质粒pSC101的复制起始蛋白是其自身顺反子的转录抑制蛋白。
DOI：
10.1073/pnas.82.8.2252
复制
发表时间：
1985
影响因子：
11.1
通讯作者：
Bastia,D
中科院分区：
文献类型：
--
作者：
Vocke,C;Bastia,D
质粒编码的pSC101复制启动蛋白特异性地抑制其天然启动子对其自身顺子的转录起始。添加纯化的引发剂对由异源启动子引发的转录几乎没有明显的影响。dna酶保护实验表明，RNA聚合酶识别序列与启动物蛋白识别序列重叠，与复制起始点相邻。利用标记的启动子序列，我们以两种方式进行了竞争性dna酶保护实验：同时加入RNA聚合酶和启动子蛋白，或依次加入RNA聚合酶和启动子蛋白到dna酶反应混合物中。无论这两种蛋白是同时添加还是顺序添加，RNA聚合酶的保护模式都是隐性的。这一观察结果表明，自调节的机制是由于两种蛋白质在启动子区域内和周围的序列竞争。此外，序列添加实验提高了RNA聚合酶被引发物蛋白从启动子中置换的可能性。
The plasmid-encoded replication initiator protein of pSC101 specifically repressed initiation of transcription of its own cistron from its natural promoter. Addition of the purified initiator had little or no visible effect on transcription initiated from a heterologous promoter. DNase protection experiments revealed that the RNA polymerase recognition sequence was overlapped by the initiator protein recognition sequences, which are vicinal to the replication origin. Using the labeled promoter sequence, we have performed competitive DNase protection experiments in two ways: by adding RNA polymerase and initiator protein simultaneously or by sequentially adding first RNA polymerase and then initiator protein to the DNase reaction mixture. The RNA polymerase protection pattern was recessive to that of the initiator regardless of whether the two proteins were added simultaneously or sequentially. This observation suggests that the mechanism of autoregulation is due to competition of the two proteins for the sequences in and around the promoter region. Furthermore, the sequential addition experiments raise the possibility of displacement of RNA polymerase from the promoter by the initiator protein.